Borosiloxanes exhibit peculiar physical characteristics which make them suitable for therapeutic use. These borosiloxane bouncing putties are shown, for example, in U.S. Pat. No. 2,541,851, issued to Wright, and U.S. Pat. No. 3,677,997, issued to Kaiser et al. Both of these patents are fully incorporated by reference herein.
These bouncing putties have the peculiar characteristic of being able to be kneaded and worked as a putty-like material, while at the same time exhibiting elastic properties under a greater degree of force. A borosiloxane bouncing putty has been commercially available as a toy under the trademark "SILLY PUTTY". Because of their characteristics, bouncing putties have found application in physical therapy to strengthen muscular control and performance of, e.g., patients' hands.